Added some documentation.

core/js/oc-vcategories.txt

@@ -17,7 +17,7 @@ Set the app specific values in your javascript file. This is what I've used for
 	OCCategories.app = 'contacts';
 	OCCategories.changed = Contacts.UI.Card.categoriesChanged;
 
-If OCCategories.changed point is set that function will be called each time the categories have been changed
+If OCCategories.changed is set that function will be called each time the categories have been changed
 in the editor (add/delete/rescan) to allow the app to update the UI accordingly. The only argument to the function
 is an array of the updated categories e.g.:
 
@@ -25,4 +25,9 @@ OCCategories.changed = function(categories) {
 	for(var category in categories) {
 		console.log(categories[category]);
 	}
-}
+}
+
+To show the categories editor call:
+
+	OCCategories.edit()
+